The present invention relates to a height adjustable table. In particular, although not exclusively, the invention relates to a height adjustable table on which a computer monitor may be mounted. However, the invention is not limited to a stand-alone table and as such may be applicable to a work station which incorporates within it, a height adjustable table portion.
Height adjustable tables are known. The type which is most commonly in use with computer monitors incorporates a pneumatic spring which assists with raising and lowering the table top by adjustment of an appropriate lever. A common difficulty with such tables is that the effect of the spring can often be unpredictable. On the one hand where the pneumatic spring is sufficiently energised, the table may move upwardly with an unexpected jerky motion. Additionally, lowering the table will require exertion on the part of the user. This may at times be difficult, especially where the user cannot position himself immediately adjacent to the table. On the other hand, pneumatic springs have a tendency to leak over time. When released, the table top may suddenly drop. On the other hand, if the user intends to raise the table top then the user may have difficulty in doing so with an ineffective pneumatic spring. Furthermore, pneumatic tables also have a tendency after a while to jam or stick creating further difficulties for the user.
It is known to provide table tops which are height adjustable. Such table tops have a dependent threaded spindle which is threadingly received within an internally threaded nut provided on a stationery base member. It is impractical in many situations to rotate a table top in order to selectively raise or lower the height of the table top. This is especially so where the table top is used to support a computer monitor with associated cables.
Accordingly, it is an object of the present invention to provide a height adjustable table assembly which overcomes or at least addresses some of the foregoing disadvantages.
In accordance with a first aspect of the present invention there is provided a height adjustable table assembly comprising: a table top having an upper surface and an outer periphery; a supporting base; and a height adjustment mechanism to selectively raise or lower the table top relative to the supporting base, the height adjustment mechanism including a height adjustment actuator in the form of a rotatable member which is selectively rotatable relative to the supporting base to actuate the height adjustment mechanism to selectively raise or lower the table top, the rotatable member being disposed underneath the upper surface of the table top and having an outer edge which terminates at or near the outer periphery of the table top for at least a portion of the outer periphery of the table top.
Preferably, the outer edge of the rotatable member is commensurate with the outer periphery of the table top or at least is closely spaced therefrom. In this manner the rotatable member operates as a hand wheel. Alternatively, where the outer edge of the rotatable member is substantially aligned with the table top for only a portion of the outer periphery of the table top, then it is preferred that said portion extends for a sector of the table top eg. 90 to 180 degrees. Suitably in any combination table arrangement incorporating the table assembly of the present invention with additional work surfaces, that sector is facing the user for ease of use.
Suitably, where the outer edge of the rotatable member terminates at or near the outer periphery of the table top then the outer edge of the rotatable member should be within reach of the user""s hand positioned at the outer periphery of the table top. This enables the user to easily rotate the rotatable member without having to excessively reach to operate the height adjustment mechanism.
In a most preferred form of the invention, the outer edge of the rotatable member and the outer periphery of the table top are both circular with their central axes aligned. However the arrangement is not limited to both parts being circular and other variations on this theme include one or both parts being polygonal with say, six or more sides. For example, the table top might be circular with an octagonal rotatable member. On the other hand, the rotatable member might be circular with an heptagonal table top. Where the outer edge of the rotatable member is made circular then it may be in the form of a circular member or alternatively in the form of an annular member. Advantageously, the rotatable member is thin and substantially planar and is closely spaced underneath the table top so as to be unobtrusive. A gripping surface such as spaced indentations may also be provided on the side and/or the underside of the rotatable member to further increase ease of use. As a possible variation, the rotatable member could even be located within the table top, provided that the outer edge of the rotatable member is accessible to the user through apertures in the side of the table top.
In the invention broadly described above, the table assembly may have more than one leg. Accordingly, the height adjustment mechanism may be provided within one leg of the table, the bottom of which acts as the supporting base. The height adjustment mechanism may include a threaded spindle which is attached to the rotatable member to thereby rotate with the rotatable member. Thus the rotatable member and the threaded spindle constitute the rotatable portions of the height adjustment mechanism. The height adjustment mechanism may further include an internally threaded nut which is fixedly mounted relative to the supporting base of said leg of the table. The threaded spindle engages in the internally threaded nut.
The internal workings of the height adjustment mechanism may be shrouded within upper and lower shrouds telescopically received one within the other. Likewise, the other legs may constitute upper and lower portions, one telescopically received within the other.
Concerning the upper shroud surrounding the height adjustment mechanism, this is preferably a cylindrical tube. Potentially, the upper shroud could rotate with the rotatable portions of the height adjustment mechanism. However, it is preferred that the upper shroud is independent of the rotational movement of the rotatable portions of the height adjustment mechanism. However it will be understood that the upper shroud moves up and down with any movement of the height adjustable table top to hide the internal workings of the height adjustment mechanism. The upper shroud may be fixed against rotational movement relative to the lower shroud. For example, guides might be provided to guide the up and down movement of the upper shroud relative to the lower shroud and thereby prevent rotation. On the other hand, an amount of rotational movement may be provided between the upper shroud and the lower shroud, this rotational movement being independent of the rotational movement of the rotatable portions of the height adjustment mechanism. This independent rotational movement may be braked, for example by providing a friction imparting device between the upper and lower shroud. The friction imparting device might be in the form of an O-ring. The additional benefit of an O-ring over another type of friction imparting device is that an O-ring will roll up and down as the upper shroud moves up and down relative to the lower shroud.
Similarly, the lower shroud advantageously comprises a cylindrical tube. The lower shroud is suitably fixed to the supporting base of the leg. In the most preferred form of the invention, the upper shroud is an inner shroud which is received within an outer shroud which is the lower shroud. However the invention is not limited to this arrangement.
As stated above, the height adjustment mechanism may be provided within one leg of a table. Preferably, the table is of the type having a single generally central support leg. In such an arrangement the outer edge of the rotatable member may be adjacent to the outer periphery of the table top about substantially the entirety of the outer periphery. This works best with a circular table top and an annular rotatable member attached to the spindle.
As set out above, the rotatable member is on the underside of the table top and preferably closely spaced to the table top. Consequently, the outer edge of the rotatable member may be flush with the outer periphery of the table top. Where the outer periphery of the table top has an inclined edge then the outer edge of the rotatable member may be similarly inclined. For example, the outer periphery of the table top may have a bevelled edge at a particular angle. The rotatable member may also have a generally bevelled edge at the same angle. Desirably, the bevel on the rotatable member substantially lines up with the bevel on the table top.
As mentioned, the rotatable member is rotatable relative to the table top. As such, the table top may be supported on the rotatable member. This is effectively achieved through the use of bearings to allow the rotatable member to rotate relative to the table top. A substantially planar circular bearing race is preferred. In this preferred form of the invention, there is preferably a device for limiting free rotation of the table top. This may be in the form of a tether to connect the table top to a lower portion of the table assembly other than rotatable portions of the height adjustment mechanism. For example, the table top may be tethered to either the upper or lower shroud. Preferably the table top is tethered to the upper shroud.
The tether may be in the form of a curved or bent rod or bar. Preferably, this curved or bent rod or bar has sufficient flexibility that in the event a user knocks his hand against the tether whilst operating the height adjustment mechanism, the tether will move away so the user does not hurt his hand. The tether will then return to its former position. If the upper shroud is able to rotate independently relative to the rotatable portions of the height adjustment mechanism then any larger force will allow the table top to turn against the resistance imparted by the friction imparting device (eg. O-ring). Thus, if the table top is unintentionally bumped it will return to its former position. However, if it is intended to rotate the table top then this can be achieved by applying a force merely sufficient to overcome the frictional resistance imparted by the O-ring.
In a preferred form of the invention, the height adjustment mechanism also includes an internal spring which upwardly biases the linearly moveable parts of the table assembly. This will assist in counteracting gravity when the user elects to raise the table top.
In accordance with a second aspect of the present invention there is provided a table assembly comprising: a table top; a support assembly for the table top, including a supporting base, the table top being rotatable relative to the supporting base; and a resiliently deformable tether interconnecting the table top and at least a portion of the support assembly.
The resiliently deformable tether may be in the form of a spring arm. The spring arm may comprise a bent or curved rod or bar. The bent rod or bar may be bent back on itself thereby defining two arms, one of which is connected to the table top and the other of which is connected to said portion of the support assembly. The arm connected to the table top may be inserted into the table top through the side thereof.
The table may be of the type which is height adjustable, hence the reason for the rotatable top. However this aspect of the invention is not limited to a height adjustable table and may be applicable to any table which is rotatable for any purpose. The table top may rest on bearings.
If the table is height adjustable then the support assembly may include a telescopic leg assembly having two telescopically cooperating members. A first of these members may comprise said portion of the support assembly to which the resiliently deformable tether is connected. A second one of the members may comprise the supporting base or may be fixedly connected thereto.
It is possible for the two telescopic members to rotate relative to one another. However, if the table top is to be stabilised by being tethered to one of the telescopic members then preferably there is a brake to resist relative rotational motion. Such a brake may be in the form of a friction imparting device placed between the two telescopic members. The friction imparting device may be in the form of an O-ring.
If the table is a height adjustable table then the height adjustment mechanism, at least in part, may be shrouded by the telescopic leg assembly. As will be appreciated, the second aspect of the invention is best implemented in a table with a single central leg assembly as the support assembly.
In accordance with a third aspect of the present invention there is provided a supporting leg assembly for a table, the leg assembly comprising first and second telescoping members wherein one of the telescoping members is rotatable relative to the other, there being an O-ring fitted between the first and second telescoping members.
Preferably, the supporting leg assembly is embodied in a table and most preferably this table is a height adjustable table with only a single central supporting leg assembly.
The two telescoping members may comprise shrouds surrounding at least part of the height adjustment mechanism. Preferably, the upper telescopic member moves with the table top and the lower telescopic member forms part of the supporting base of the table or rather is fixed to the supporting base. Any of the features described in the first two aspects above may be incorporated into the supporting leg assembly according to the third aspect of the present invention.